Data from: Effects of individual-based preferences for colour-banded mates on sex allocation in zebra finches

Sex allocation theory predicts that females mated to attractive males
produce more sons than females mated to unattractive males. However,
previous tests of this hypothesis have obtained mixed results. We suggest
that females differ in the traits they find attractive. To test this
proposition, we assessed female zebra finches’ preferences for males
banded with red or green plastic leg bands and then tested the sex
allocation pattern of females paired with preferred and non-preferred
males. Although most females preferred red-banded males, 34% of females
consistently preferred green-banded males. The sex ratio at laying and
hatching was not influenced by paternal preferred status. However, the
fledging sex ratios differed between females paired with preferred and
non-preferred males due to sex-biased chick mortality; sons of females
paired with preferred males were born heavier and were more likely to
survive than daughters. Our results indicate that female zebra finches
show individual variation in their preferences for colour banded males,
although females do not seem to adjust the offspring sex ratio in response
to their mate’s band colour. However, the differential post-hatch
mortality suggests females may differentially allocate resources into male
and female eggs according to their individual mate preferences.